Clinical analysis for an unusual large cystic meningioma: case report and review of the literature.

The authors report the case of a 17-year-old boy with an unusual large cystic meningioma (Nauta type II) in the right hemisphere. The imaging appearances of this patient were very unusual. The shape of the huge cyst was crescentic and similar to subdural hematoma. It lay between the dura and the solid tumor parts. In addition there was a small intracystic nodule attached to the cyst wall. The patient underwent a right hemisphere craniotomy. At surgery it was found that the cyst contained a large amount of xanthochromic fluid and some semitransparent serumlike sediment. The intracystic nodule was proved to be necrotic substance without tissue and cell structure. Histological examination displayed an anaplastic meningioma, of which the cyst wall also consisted of meningioma tissue.